The present invention relates to a thermal transfer overprinter, especially to its printing-driving control device and method applied in flexible packaging.
The working process for existing thermal transfer overprinters is as follows: when coder gets a printing signal, the cylinder or the electromagnet drives the print-head down, giving contact force between ribbon and packing film. Meanwhile, control system controls print-head to heat and to print ribbon's ink layer onto the film. After printing, control system controls air cylinder to deflate or electromagnet to cut off power so that print-head goes back (at this point, print-head is away from the film so that the ribbon could be wound up and the film could move for a small distance preparing for next print.
At the present, the driving principle for the print-head's going down and up is achieved by means of pneumatic control or electromagnet control. The pneumatic control needs more spare parts so it's more costly and complicated in installation. Besides, the lack of air source in many application fields can also affects its functioning. Although electromagnet control does not need air source, we need high power electromagnet to provide enough stress for driving print-head. So the size of electromagnet is big and the mechanical construction of electromagnet control system is relatively complex and has higher requirements and cost for machine design and installation.
Therefore, technicians in this field are making great efforts to develop a set of new and modified printing-driving control device for thermal transfer overprinter.